This how to is a set of instructions for rebuilding libgraphicsmagick so it can process 16 bit images and rebuilding octave so it can take advantage of the new graphicsmagick libraries. This document assumes you’ve already installed octave using a package manager so that all of it’d dependencies have been resolved. Read over the entire how to before executing it. I do _not_ recommend you copy and paste it as a shell script and run it. Pay attention to each step and examine each command before hitting enter; I may have made a few typos.